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What kinda problem do i have?

Discussion in '1982-Present GM Diesel' started by savagek5diesel, Jul 5, 2005.

  1. savagek5diesel

    savagek5diesel 1/2 ton status

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    hey guys, i was out on the trail for a weekend camping trip and while i was waiting for a friend to get his turd up a snow pack, my truck slowly died out. i was able to fire it up right after it happened but it died just 3 or 4 seconds later. i have fuel to the injectors, so i'm thinking the problem is with the fuel return line. is this right? the IP has power and is working right also. the only thing i could figure is that the extremly dusty road up there (because i was following) put a bunch of dirt into the engine to clog things up.
    Also, while trying to start it over and over i managed to burn up some electrical somewhere, i have no power to the cab, and no volt readings to the battery's anymore, i think i just need to replace the wiring that goes to the coil on the starter. any idea's what to check for and how i should go about replacing this stuff? thanks for any input guys.
    AJ
     
  2. kennyw

    kennyw N9PHW Premium Member

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    It sounds like you ran the motor out of fuel the way it died then partially fired again. I would honestly suspect your lift pump is failing or has failed. But try putting 5 gallons in the tank first and check to see if the lift pump is working.

    As far as the electrical you probably burned up the positive battery lead from cranking too much with out proper cooling time or the fuseable links off the starter that route power to the cab.
     
  3. shaun

    shaun 1/2 ton status

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    For electrical check the ignitor wire from your ignition module to the starter. I somehow shorted mine trying to start my truck (I had run it out of fuel previous owner did not tell me the fuel gauge was off and I didnt check)
     
  4. savagek5diesel

    savagek5diesel 1/2 ton status

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    hey guys, i couldn't have run out of fuel because i had over a half tank and i was sitting on level ground, and i have fuel pressure down to the injectors. as far as electrical goes, i know im gonna need to replace the accesories wire down to the starter because it's nice and crispy at the moment. would it be a good idea to replace that wire without a fusible link? and if no, what size fuse should it be replaced with? thanks guys, and please keep your input coming. this is a DD.
     
  5. kennyw

    kennyw N9PHW Premium Member

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    If you had real fuel pressure at the injectors (enough to open your injectors) your motor would run with or without any electical voltage. My guess is your lift pump is partially working but not enough to get the proper supply pressure from the injector pump or worse yet your injector pump failed and is loosing pressure internally. But I would replace the $15 lift pump first, bleed the lines and go from there.
     
  6. savagek5diesel

    savagek5diesel 1/2 ton status

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    back to the electrical

    alright, i replaced some wires down on the starter, my fusible links were good still. but the problem i'm against now is my Purple ignition wire, isn't getting power anymore. I've already got a manual start switch on the dash to engage the starter, but now that purple wire isn't getting power and i can't turn the engine over so i can further diagnos what's wrong with my truck. any idears?
     
  7. kennyw

    kennyw N9PHW Premium Member

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    So you have power in the cab now, but no power to your ignition circuit?
     
  8. savagek5diesel

    savagek5diesel 1/2 ton status

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    yes

    i have power to the cab and the yellow constant from the ignition cylinder, but nothing to the purple ignition wire.
     
  9. diesel4me

    diesel4me 1 ton status Premium Member

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    neutral safety??

    That purple wire goes from the ignition switch,to the neutral safety switch,then to the solenoid...might not be getting past the neutral safety if its got power at the ignition..unless you have it By-passed with a jumper wire so it will start in any gear--in that case the wire might be fried or cut somewhere...or no power is coming from the ignition TO the purple wire..did you check the fusible link near the power brake booster at the junction block??.. :crazy:
     
  10. savagek5diesel

    savagek5diesel 1/2 ton status

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    purple wire

    yes, the fusible link on the junction block is good. but the thing that gets me is i ran 12v through the purple wire down at the starter selenoid end, then went into the cab and checked it and i had power all the way up to my switch. so does this mean the safety switch is bad? thanks fer the help guys, keep it coming please.
     
  11. diesel4me

    diesel4me 1 ton status Premium Member

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    lets try again...

    OK--so you removed the purple wire from the solenoid,and applied 12V to it..and the current makes it all the way to the ignition switch??...sounds like the neutral safety is working,for it interrupts the current from the ignition to the solenoid...but since you have a pushbutton to acctivate the solenoid,I dont see why the ignition switch is even a suspect..the pushbutton switch only needs a 12V hot lead,and the other side goes to the purple wire to activate the solenoid..the ignition will only control the hot wire to the HEI and all other accessories,it no longer controls the "cranking" if its been moved to the pushbutton... :confused:

    Will it crank if you jump the solenoid??...if it does,I'd say it has to be a bad spot in that purple wire somewhere,just because you can get a test light to light up does not mean its in good enough shape to pass enough amps to engauge the solenoid...I'd run a new 12ga wire to the solenoid,and make sure the 12v source to the pushbutton is a good one..once you get it to crank over again,we can move on to the other problems!... :doah: :crazy:
     
  12. savagek5diesel

    savagek5diesel 1/2 ton status

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    stupid purple wire

    well i replaced any section of wire that was charred or hardened that went down to to the selenoid. so what you're saying is that the purple wire does not have power running through it until the constant 12v from the push button (or key) ignition is pressed? this being, my push button ignition prolly went bad because everything else is working up to par. which makes sense because lately it has taken a couple pulls on the switch to get it to bump over. thanks diesel4me and everyone else that has helped so far. i will keep you updated, and will be needing more info as soon as i can get it to start turning over again.
     
  13. savagek5diesel

    savagek5diesel 1/2 ton status

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    update

    alright, turns out that my inginition switch was bad, replaced it and now i can turn the truck over again. So now what should i start checking so the thing will run again?
     
  14. diesel4me

    diesel4me 1 ton status Premium Member

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    Well...

    Well!..at least THATS fixed!..its not very common for an ignition switch to "go" in a chevy..I've had quite a few GM trucks,but never had a bad ignition switch(yet!)..maybe I'm just lucky!--I've had many you could remove the keys from while in the "on" position,but never had one croak yet.. :confused:


    Now that it cranks,turn the key to "ON",and check for 12V at the fuel shutoff solenoid at the injector pump(big pink or red wire)..it needs 12V to open the solenoid and let fuel in the injector pump.(you could simply pull off the wire and touch it to the solenoid and listen for a "click"to see if its geting juice)..your correct in assuming the return line if clogged,wil cause the motor to stall..(thats how you shut off a GM diesel if it wont stop after turning the key off-pinch the return line shut!).



    If you have fuel to the injectors,and the glow plugs are working,it should start unless air got into the fuel lines,in that case you'll have to loosen all the injector lines,and crank it over until fuel appears at them,then retighten the lines and try again...if your glowplugs are on a manual switch,you could use WD-40 as starting fluid to help coax it back to life...get the motor cranking,and spray the WD-40 into the intake,but DO NOT activate the glow plugs,or it will likely damage a piston or valve!..I'd avoid using Ether,its too explosive in summer weather,and beats the hell out of the internal parts..

    Try this and see what happens..if you still have no luck,I'm sure others here and myself will be willing to try and help..good luck! :crazy:
     
  15. savagek5diesel

    savagek5diesel 1/2 ton status

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    Alrighty, the fuel selenoid passed the test, so that isn't my problem any more. What i'm trying to figure out is HOW can you unclog a fuel return line? do you replace it? everything i've read in manuals and through the ck5 archives just says "you probably have a clogged fuel return line" and then nothing with a follow up. So hopefully i can squeez some more information out you guys. It's so close to running i can feel it. thanks again everybody.
     
  16. savagek5diesel

    savagek5diesel 1/2 ton status

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    Alrighty, the fuel selenoid passed the test, so that isn't my problem any more. What i'm trying to figure out is HOW can you unclog a fuel return line? do you replace it? everything i've read in manuals and through the ck5 archives just says "you probably have a clogged fuel return line" and then nothing with a follow up. So hopefully i can squeez some more information out you guys. It's so close to running i can feel it. thanks again everybody.

    oh yeah, and DIESEL4ME, incase you didn't know already.... I have the best luck in the world with with cars and trucks that i own. seems like the most bizarre, rare mishaps always strike me. hahaha :doah:
     
  17. kennyw

    kennyw N9PHW Premium Member

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    You can buy new return lines in a kit for about $28. They come in an Injector Install Kit.

    Diesel Injection Service
     
  18. savagek5diesel

    savagek5diesel 1/2 ton status

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    could this be it?

    hi guys, couple things i noticed today while working on my truck was.... i was squeezing each fuel return line and all of them but two (pass. side, the first two in the front) didn't have pressure., the other two were stiff. Should all the lines be pressured or soft?
    Question number two is...... i have a leak on the IP on the right side of the pump. i can't find exactly what it's called, but it's the spring loaded lever above the idle adjustment screw and it's leaking pretty good from there. about 10-12 drops after you try and start the truck. Any ideas on what to do now? thanks again.
     
  19. kennyw

    kennyw N9PHW Premium Member

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    None of the return lines should be pressurized. They are possibly blocked at that point.
     
  20. savagek5diesel

    savagek5diesel 1/2 ton status

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    what i did was shoot a little bit of air down the return line until i heard it push all the fuel into the gas tank. Is this a yay or nay?
     

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